Space Transportation System solid rocket booster thrust vector control system

The Solid Rocket Booster, Thrust Vector Control (TVC) system was designed in accordance with the following requirements: self-contained power supply, failsafe operation, 20 flight uses after exposure to seawater landings, optimized cost, and component interchangeability. Trade studies were performed which led to the selection of a recirculating hydraulic system powered by Auxiliary Power Units (APU) which drive the hydraulic actuators and gimbal the solid rocket motor nozzle. Other approaches for the system design were studied in arriving at the recirculating hydraulic system powered by an APU. These systems must withstand the imposed environment and be usable for a minimum of 20 Space Transportation System flights with a minimum of refurbishment. The TVC system completed the required qualification and verification tests and is certified for the intended application. Substantiation data include analytical and test data

The Role of Mentoring in Developing Professional and Personal Competencies for School Administrators

In the state of Georgia and across the nation there was a shortage of principals. A new supply of administrators was needed to guide education through the 21st century. These leaders needed updated knowledge and skills to address the needs of an educational system affected by educational reform. Effective leadership allowed administrators to view situations in both the eyes of management and leadership. A mentoring program for beginning administrators provided guidance in developing these skills and in recruiting and retaining individuals for these critical positions. The purpose of this study was to examine the perceptions of a mentoring program for mentored principals. This qualitative study analyzed data from two groups. One group consisted of eight principals from Georgia who had varied experiences with mentoring either prior to becoming a principal or during their first or second year as a principal. The second group consisted of four principals from Kentucky who participated in a required formal mentoring program during their first year as a principal. A set of twenty questions was used in a semi-structured interview process. The software program, QSR NUDIST (N5), was used to help identify patterns and themes in the participants\u27 responses. Following are the major findings yielded from the data. First, all participants thought it was important to have a mentor. Participants wanted individuals who wanted to be their mentor and cared about their success. The main benefits from mentoring were: the confidentiality and trust between the proteges and mentors; the mentor serving as a role model and providing knowledge, experience and resources; guided instruction that provided help with problem solving and on-the-job practice; and help with career path and job advancement. Several participants recognized that mentors helped reduce the isolation/loneliness of the principal position. Others noted that positive mentoring experiences made them want to mentor others who were aspiring to be administrators. Finally, although both formal and informal mentoring experiences had significant effects upon the participants, those in formal mentor programs perceived greater benefits than those who participated in informal mentorships. These findings enabled the researcher to make several recommendations for mentoring programs for entry-level administrators

Optical signature of symmetry variations and spin-valley coupling in atomically thin tungsten dichalcogenides

Motivated by the triumph and limitation of graphene for electronic applications, atomically thin layers of group VI transition metal dichalcogenides are attracting extensive interest as a class of graphene-like semiconductors with a desired band-gap in the visible frequency range. The monolayers feature a valence band spin splitting with opposite sign in the two valleys located at corners of 1st Brillouin zone. This spin-valley coupling, particularly pronounced in tungsten dichalcogenides, can benefit potential spintronics and valleytronics with the important consequences of spin-valley interplay and the suppression of spin and valley relaxations. Here we report the first optical studies of WS2 and WSe2 monolayers and multilayers. The efficiency of second harmonic generation shows a dramatic even-odd oscillation with the number of layers, consistent with the presence (absence) of inversion symmetry in even-layer (odd-layer). Photoluminescence (PL) measurements show the crossover from an indirect band gap semiconductor at mutilayers to a direct-gap one at monolayers. The PL spectra and first-principle calculations consistently reveal a spin-valley coupling of 0.4 eV which suppresses interlayer hopping and manifests as a thickness independent splitting pattern at valence band edge near K points. This giant spin-valley coupling, together with the valley dependent physical properties, may lead to rich possibilities for manipulating spin and valley degrees of freedom in these atomically thin 2D materials

Self-management, time management, and personality type

The relationships between self-management, time- management, and personality types and the results dimensions were examined in this study. The sample consisted of 347 undergraduate and graduate students ranging in age from 18 to 53. Most of the subjects (N=296) came from an undergraduate course in Psychoeducational Issues in Human Development, which was organized along self-directed lines. The remaining subjects (N=51) came from an undergraduate course entitled Exploring Majors and Careers. A separate part of the study was conducted on a sample of 77 undergraduate students to examine the test-retest reliability of the TMQ. The subjects were given the Time Management Questionnaire (TMQ), Lifestyle Approaches Inventory (LSA), and Myers-Briggs Type Indicator (MBTI). Additionally, the Marlowe Crowne instrument was administered to measure social desirability response tendencies. The TMQ, LSA, and MBTI were administered to intact classes by the experimenter and other members of a self-management research team. Students were given the option of refusing to participate in the study without any penalty. Nearly all elected to participate. The TMQ, LSA, MBTI, and Marlowe Crowne were subsequently scored by trained graduate students. The results showed that the TMQ is a relatively reliable instrument for assessing time management perspectives. The Short Range Planning factor yielded the highest test-retest reliability (.85) and Long Range Planning the lowest (.52). All of the TMO factors were significantly related to all the LSA factors. The LSA total was most strongly related to the Time Attitudes factor of the TMQ, and the TMQ total was most strongly related to the Timeliness of Task Accomplishment factor of the LSA. Both the TMQ and the LSA factors showed relatively strong and consistent correlations with the Judging- Perceiving dimension of the MBTI. Some of the LSA and TMQ factors were also significantly (but weakly) correlated with the Extraversion-Introversion and Sensing-Intuition dimensions of the MBTI. However, these latter correlations accounted for a very small percentage of the variance in the comparison variables. Stepwise multiple regression analyses revealed that the MBTI dimensions (especially the JP dimension) were more predictive of the TMQ-Total than of the LSA Total. The MBTI dimensions that most distinguished the Myers- Briggs types obtaining the highest and lowest scores on the LSA were JP and SN. Apparently, individuals who prefer to be realistic and practical and who emphasize planning and organization are better self-managers than those who prefer imaginative possibilities and who emphasize spontaneity and flexibility

Anomalous Lattice Vibrations of Single and Few-Layer MoS2

Molybdenum disulfide (MoS2) of single and few-layer thickness was exfoliated on SiO2/Si substrate and characterized by Raman spectroscopy. The number of S-Mo-S layers of the samples was independently determined by contact-mode atomic-force microscopy. Two Raman modes, E12g and A1g, exhibited sensitive thickness dependence, with the frequency of the former decreasing and that of the latter increasing with thickness. The results provide a convenient and reliable means for determining layer thickness with atomic-level precision. The opposite direction of the frequency shifts, which cannot be explained solely by van der Waals interlayer coupling, is attributed to Coulombic interactions and possible stacking-induced changes of the intralayer bonding. This work exemplifies the evolution of structural parameters in layered materials in changing from the 3-dimensional to the 2-dimensional regime.Comment: 14 pages, 4 figure

Experimental evidence of strong phonon scattering in isotopical disordered systems: The case of LiH_xD_{1-x} crystals

The observation of the local - mode vibration, the two - mode behavior of the LO phonons at large isotope concentration, as well as large line broadening in LIH - D mixed crystals directly evidence strong additional phonon scattering due to the isotope - induced disorder.Comment: 9 pages, 4 figure

Integration mockup and process material management system

Work to define and develop a full scale Space Station Freedom (SSF) mockup with the flexibility to evolve into future designs, to validate techniques for maintenance and logistics and verify human task allocations and support trade studies is described. This work began in early 1985 and ended in August, 1991. The mockups are presently being used at MSFC in Building 4755 as a technology and design testbed, as well as for public display. Micro Craft also began work on the Process Material Management System (PMMS) under this contract. The PMMS simulator was a sealed enclosure for testing to identify liquids, gaseous, particulate samples, and specimen including, urine, waste water, condensate, hazardous gases, surrogate gasses, liquids, and solids. The SSF would require many trade studies to validate techniques for maintenance and logistics and verify system task allocations; it was necessary to develop a full scale mockup which would be representative of current SSF design with the ease of changing those designs as the SSF design evolved and changed. The tasks defined for Micro Craft were to provide the personnel, services, tools, and materials for the SSF mockup which would consist of four modules, nodes, interior components, and part task mockups of MSFC responsible engineering systems. This included the Engineering Control and Life Support Systems (ECLSS) testbed. For the initial study, the mockups were low fidelity, soft mockups of graphics art bottle, and other low cost materials, which evolved into higher fidelity mockups as the R&D design evolved, by modifying or rebuilding, an important cost saving factor in the design process. We designed, fabricated, and maintained the full size mockup shells and support stands. The shells consisted of cylinders, end cones, rings, longerons, docking ports, crew airlocks, and windows. The ECLSS required a heavier cylinder to support the ECLSS systems test program. Details of this activity will be covered. Support stands were designed and built for each module to sufficiently move and rotate each module. Secondary structures such as floors, ceilings, bulkheads, standoffs, racks, etc. were developed and built

Occurrence of Camponotus Pennsylvanicus (Hymenoptera: Formicidae) in Trees Previously Infested with Enaphalodes Rufulus (Coleoptera: Cerambycidae) in the Ozark Mountains of Arkansas

Black carpenter ants, Camponotus pennsylvanicus (DeGeer), are nearly ubiquitous in North American forests. These ants are documented as predators of red oak borer, Enaphalodes rufulus (Haldeman), a native longhorn beetle that experienced an unprecedented population increase synonymous with an oak decline event in the oak hickory forests of the Ozark Mountains of Arkansas from the late 1990s until 2005. We examined previous red oak borer emergence holes, tree crown conditions, and site aspects in 13 pre-established vegetation monitoring plots and correlated these forest and tree attributes with the presence or absence of black carpenter ants. At each site, all red oaks \u3e 10 cm diameter at breast height were baited for black carpenter ants with a mixture of tuna and honey. Black carpenter ants were more frequently found on trees with low levels of previous red oak borer infestation versus those trees with previously high infestations. These data suggest a potential role for black carpenter ants in the dynamics of red oak borer populations. Distribution of black carpenter ants in red oaks prior to and during the outbreak is unknown. Future investigations should be directed at efforts to understand whether black carpenter ants simply prefer different tree and site attributes than red oak borer or if, via predation, these ants are acting as agents of red oak borer control

Insect Collection Methods at Fort Leonard Wood

This project is part of a larger survey examining the terrestrial insect diversity at Fort Leonard Wood in summers 2021 and 2022. The data analyzed in this poster includes specimens collected during the 2022 collection period. This project attempts to elucidate the most effective method of insect collection at Fort Leonard Wood, as well as any hotspots of insect presence or diversity on the base. Specimens were collected using hand and net collection, Lindgren funnel trapping, leaf litter sampling, and three colors of pan trapping (blue, yellow, white). Specimens were processed in the lab, pinned, sorted, and identified. Preliminary analysis shows that hand trapping methods collected insects of more differing orders than all other methods in a manner that was statistically significant compared to all methods except white pan traps (Shannon Diversity t-test, p \u3c 0.001). These results will better inform future insect collection methods at Fort Leonard Wood and beyond